I Ontology Representation and Reasoning -- 1 Description Logics -- 2 Ontologies in F-logic -- 3 The Resource Description Framework (RDF) and its Vocabulary Description Language RDFS -- 4 Web Ontology Language: OWL -- 5 An Ontology-Composition Algebra -- II Ontology Engineering -- 6 On-To-Knowledge Methodology (OTKM) -- 7 Building a Very Large Ontology from Medical Thesauri -- 8 An Overview of OntoClean -- 9 Ontology Learning -- 10 Knowledge Patterns -- 11 Ontology and the Lexicon -- 12 Ontology Reconciliation -- 13 Ontology Evaluation -- 14 Ontology Engineering Environments -- III Ontology Infrastructure -- 15 An Extensible Ontology Software Environment -- 16 Ontologies in Support of Problem Solving -- 17 Ontologies in Agent Architectures -- 18 Tools for Mapping and Merging Ontologies -- 19 Ontology Matching: A Machine Learning Approach -- 20 Retrieving and Exploring Ontology-based Information -- 21 Supporting User Tasks through Visualisation of Light-weight Ontologies -- IV Ontology Applications -- 22 Ontologies for Knowledge Management -- 23 Ontology-based Content Management in a Virtual Organization -- 24 Ontology-based Recommender Systems -- 25 The Knowledge Portal "OntoWeb" -- 26 Ontologies and Hypertext -- 27 Semantic Layering with Magpie -- 28 Ontologies and Metadata for eLearning -- 29 Ontology of the Process Specification Language -- 30 The Role of Ontologies in eCommerce -- 31 An Ontology-based Platform for Semantic Interoperability -- 32 Ontologies in Bioinformatics -- Author Index.